The Complete Handbook of Jigs

Chapter 1: Understanding Jigs

A jig is a guiding device. It holds a tool, or a workpiece, precisely so that the tool follows a predetermined path. This is not a specialized or exotic concept. It is a fundamental principle of practical work. From a simple drill bushing that keeps a bit perpendicular to a surface, to a complex welding fixture that locates multiple parts for assembly, a jig's entire purpose is to remove guesswork from the hand and eye. The core function is always the same: to physically constrain the motion of a tool in every axis where human error is likely to occur.

Think about driving a deck screw without a pilot hole. The drill can wander across the face of the board, or the bit can enter at a slight angle, causing the screw to emerge from the side of the workpiece. Now consider a steel drill bushing pressed into a phenolic base. The bit enters the bushing, the bushing is perpendicular to the base, and the base is clamped flat against the stock. You cannot miss your mark, and you cannot drill at the wrong angle. The jig has turned a skilled, delicate operation into a simple matter of pulling a trigger. That is the core premise of every jig in this handbook.

This principle extends far beyond the drill press table. In a production cabinet shop, a router template jig for cutting hinge mortises is not an option; it is a requirement for meeting production quotas.